One way to reduce the demand for fresh water is to reclaim waste water for human and animal consumption and other uses. However, public concerns about residual contaminants, such as endocrine disrupting compounds (EDCs), pharmaceutically active compounds (PhaCs), pathogens, and other contaminants, have limited the acceptance of reclaimed water slowed the adoption of water treatment technologies. Of notable concern among organic compound contaminants are ethynyl estradiol, triclosan, DEET, surfactants, nonylphenol (NP), triclosan (TCS), and Bisphenol-A (BPA). Of particular concerns among biological contaminants are pathogens such as coliforms, poliovirus, and Cryptosporidium. 
Concerns over residual biological and chemical contaminants has prompted the adoption of various laws, regulations, and standards concerning public water supplies, such as California Code of Regulations (CCR), Title 22. Among other criteria, Title 22 requires waste water to be treated by a chlorine disinfection process following filtration that provides a product of total chlorine residual and modal contact time measured at the same point of not less than 450 milligram minutes per liter (mg-min/L) at all times with a modal contact time of at least 90 minutes, based on peak dry weather design flow; or a disinfection process that, when combined with the filtration process, has been demonstrated to inactivate and/or remove 99.999 percent of the plaque-forming units (pfus) of F-specific bacteriophage MS2, or polio virus in the waste water. A virus that is at least as resistant to disinfection as poliovirus may be used for purposes of the demonstration. Title 22 requires also requires that the (a) median concentration of total coliform does not exceed 2.2 MPN/100 mL, (b) no more than 23 MPN/100 mL coliforms are present in any one sample in a 30-day period, and (c) that no sample shall contain a exceed 240 MPN/100 mL coliforms. Title 22 further requires at least a 5-log reduction in the levels of poliovirus, or an equivalent reduction in a suitable representative water-borne virus. Many states have similar regulations and standards.
The thorough removal of coliforms, viruses, and other biological contaminants, generally referred to as “disinfection,” increases the cost of reclaiming waste water, particularly using convention water treatment methods, such as reverse osmosis (RO), ultrafiltration (UF), and advanced oxidative procedures (AOP), where the cost of setting up a 1-million gallon-per-day (1 meg gpd) treatment facility is on the order of $10 meg USD.
Ozone alone (or in combination with oxygen or air) can be used in an “ozone dissolution” process for oxidizing many waterborne contaminants. The process is relatively inexpensive, particularly when ozone is generated on site. Ozone in combination with hydrogen peroxide can be used in an “advanced oxidation” process, which produces hydroxyl radicals (see Equation 1, below), which are even more effective in removing some contaminants.2O3+H2O2→2OH.+3O2  (Eq. 1)
Water treatment technologies that use ozone (O3), or ozone in combination with hydrogen peroxide (H2O2), to destroy organic compounds present in contaminated water can be effective, but the cost and complexity of the equipment necessary to perform the process preclude its widespread adoption.
The need exists for more efficient and easier to install, operate, and optimize ozone dissolution and advanced oxidation apparatus for water contaminant removal, that can be incorporated into the design of new facilities and adapted to existing treatment facilities.